PROBLEM TO BE SOLVED: To provide means capable of effectively suppressing temperature rise of light-emitting diodes in a mode where heat that moved from the light-emitting diodes to cooling water can be rationally processed or used.SOLUTION: A seedling raising device comprises: a seedling raising chamber 7 which houses seedlings of a domesticated plant light-emitting diodes equipped with an illumination device which irradiates the seedlings housed in the seedling raising chamber 7 with light and a cooling water circulation passage 43 a part of which is arranged in the vicinity of the light-emitting diode and through which cooling water flows in a circulating manner. The seedling raising device further comprises: a heat exchanger 45 an external air introduction passage 48 an air discharge passage 49 an internal air introduction passage 50 and an air inflow passage 51. Herein, the heat exchanger 45 has: a cooling water flow channel 46 which is interposed to the cooling water circulation passage 43 and communicates with the cooling water circulation passage 43 and an air flow channel 47 for allowing air to circulate, and increases the temperature of air while reducing the temperature of cooling water by heat exchange between the cooling water and air.SELECTED DRAWING: Figure 8COPYRIGHT: (C)2017,JPO&INPIT【課題】発光ダイオードから冷却水に移動した熱を合理的に処理ないしは利用できるような態様で、発光ダイオードの温度上昇を効果的に抑制することができる手段を提供する。【解決手段】苗育成装置は、栽培用植物の苗を収容する育苗室7と、育苗室7に収容されている苗に光を照射する発光ダイオードを備えた照明装置と、その一部が発光ダイオードの近傍に配置されその内部を冷却水が循環して流れる冷却水循環通路43とを備えている。苗育成装置は、さらに、熱交換器45と、外気導入通路48と、空気排出通路49と、内気導入通路50と、空気流入通路51とを備えている。ここで、熱交換器45は、冷却水循環通路43に介設され該冷却水循環通路43と連通する冷却水流路46と、空気を流通させる空気流路47とを有し、冷却水と空気との間の熱交換により、冷却水の温度を低下させる一方空気の温度を上昇させる。【選択図】図8
